This invention relates generally to linear actuator devices and in particular to piezoelectric linear actuators utilizing motion amplification.
Many piezoelectric or electroexpansive actuators of the prior art utilized various lever arm arrangements by which the lever arm was pivotally connected to a fixed support with the piezoelectric member placed in compression against the lever arm a short distance from the pivot point. The motion amplification was achieved at the end of the lever arm distal the pivot point and was based upon the ratio of the distance from the pivot point of the piezoelectric member and the end point of the lever arm away from the pivot point.
Other devices used to achieve motion amplification for piezoelectric actuators involved the use of hydraulic amplification in which the piezoelectric member was used to move a piston having a large surface area moving an hydraulic fluid. The hydraulic fluid was then used to drive a smaller area piston a greater distance. The motion amplification was directly proportional to the ratio of piston areas.
In all of the prior art devices the mass of the mechanical amplifying systems were large resulting in a limitation of the reaction time of the linear actuator.